Dysfunction of fat cells is strongly associated with the development of obesity and insulin resistance. The regulation of the expression of kinases by fat cells is an important target for the prevention of obesity and improvement of insulin sensitivity. Guo et al extracted this anthocyanin from black rice, which contains significant amounts of cyanidin 3-glucoside, and tested its protective effect on insulin sensitivity in cultured fat cells, which were exposed to hydrogen peroxide or tumor necrosis factor alpha. They found that cyanidin 3-glucoside attenuated hydrogen peroxide or TNF-alpha-induced insulin resistance in a dose-dependent manner . Pretreatment of the fat cells with cyanidin 3-glucoside reduced the intracellular production of reactive oxygen species and the activation of Jun N-terminal kinases. Cyanidin 3-glucoside also improves insulin sensitivity by regulating the glucose transporter 4 and retinol binding protein 4 system . Glucose transporter 4 is the glucose transporter found in adipose tissues and striated muscle and is regulated by insulin. Glucose transporter 4 is sequestered in the interior of the cell and is activated by insulin. The activated glucose transporter 4 migrates to the cell membrane where it facilitates the passive diffusion of glucose into the cells. Once inside cells, glucose is phosphorylated to glucose-6-phosphate, which cannot diffuse back out of cells. Retinol binding protein a kinase in fat cells that can contributes to insulin resistance. Cyanidin 3-glucoside reduces blood glucose level and improves insulin sensitivity due to the reduction of retinol binding protein 4 expression in type 2 diabetic mice.
Purple corn is rich is cyanidin and is used in Japan for colouring of food. Takanori et al found that cyanidin glucoside from purple corn extract could be used to treat obesity and diabetes. They came to that conclusion after testing the effect of the phytochemcial on mice. A high fat diet induced hyperglycemia, hyperleptinemia and hyperinsulinemia in the mice, effects that were inhibited by the intake of cyanidin. Dietary cyanidin suppressed the increase in the liver total lipids and triacylglycerol concentrations by reducing the mRNA levels of enzymes needed to synthesize fatty acids and triacylglycerol .
 Guo H, Ling W, Wang Q, Liu C, Hu Y, Xia M. "Cyanidin 3-glucoside protects 3T3-L1 adipocytes against H(2)O(2)- or TNF-alpha-induced insulin resistance by inhibiting c-Jun NH(2)-terminal kinase activation." Biochem Pharmacol. 2007 Dec 3.
 Sasaki R, Nishimura N, Hoshino H, Isa Y, Kadowaki M, Ichi T, Tanaka A, Nishiumi S, Fukuda I, Ashida H, Horio F, Tsuda T. "Cyanidin 3-glucoside ameliorates hyperglycemia and insulin sensitivity due to downregulation of retinol binding protein 4 expression in diabetic mice." Biochem Pharmacol. 2007 Dec 3;74(11):1619-27.
 Takanori T, Fumihiko H, Kaji U, Hiromitsu A and Thoshihiko O. " Dietary cyanidin 3-O-beta-D-glucoside rich purple corn color prevents obesity and ameliorates hyperglycemia in mice". J. Nutr. 133:2125-2130, Jul 2003